1. Field of the Invention
The present invention relates to a thin film forming apparatus and a thin film forming method with which it is possible to transfer a thin film, such as an insulation film and a metallic film, to a thin film bearing surface of a substrate and accordingly dispose the thin film.
2. Description of the Related Art
Over the recent years, it has became necessary to use a thin film forming method suitably applicable to a large area size as wafers used during manufacturing of LSIs have became larger in diameter, liquid crystal panels have became larger in area size, etc. In addition, in the field of multilevel interconnections techniques among techniques for manufacturing LSIs, as the surface of an insulation film needs be planarized accurately to realize multilevel interconnection. There are increasing demands for larger area sizes and better surface planarization techniques for planarization of surfaces during fabrication of thin films. In an effort to satisfy these demands, thin film forming techniques for forming a thin film on a substrate by a pressure transfer method have been proposed.
This type of thin film forming apparatus may be an apparatus which is described in Japanese Patent Application Laid-Open Gazette No. H10-189566 for instance. In this apparatus, a thin film is disposed on a substrate following thin film forming steps which are shown in FIGS. 8A through 8D. First, as shown in FIG. 8A, a substrate 1, such as a semiconductor wafer and a glass substrate for liquid crystal panel, is placed on a specimen holder in such a manner that electrode interconnections 11 formed on a surface of the substrate 1 direct themselves to above. In this example, the surface 12 seating the electrode interconnections 11 serves as a thin film bearing surface on which a thin film is to be disposed through steps described below.
Next, as shown in FIG. 8B, a sheet film F whose surface already seats an insulation film 21 is mounted to a transfer plate which is located above the specimen holder to face the specimen holder. In this example, the insulation film 21 is the thin film which is to be transferred onto the substrate 1. The insulation film 21 is located so as to face the thin film bearing surface 12 of the substrate 1 which is held on the specimen holder. The specimen holder is moved toward the transfer plate and the substrate 1 and the sheet film F are accordingly brought into contact with each other. Thereafter the substrate 1 and the sheet film F are pressed against each other as denoted at the arrows in FIG. 8B for a certain period of time while heating the substrate 1 to a predetermined temperature. As a result, the substrate 1 and the sheet film F tightly adhere to each other with the insulation film 21 inserted between the two, and a tightly adhered object is obtained.
Thus obtained tightly adhered object is taken out from a thin film forming chamber and the sheet film F is peeled off as shown in FIG. 8C, whereby the insulation film 21 is transferred onto the thin film bearing surface 12 of the substrate 1 as shown in FIG. 8D.
By the way, as described above, in a conventional thin film forming apparatus, the insulation film (thin film) 21 is formed on the sheet film F which is flexible in advance. The insulation film 21 is transferred onto the substrate 1 as the sheet film F is peeled off after joining the insulation film 21 to the thin film bearing surface 12 of the substrate 1. Hence, once the sheet film F is used, this sheet film F can not be used again. The sheet film F is thus treated as disposable goods so to speak. The sheet films F after transfer of thin films are waste and one of causes to increase a running cost.
Further, once human operators handle transportation of the sheet films F, particles may adhere to the sheet films F or heat may dissipate from the sheet films F. This makes it difficult to control heat histories and leads to a deterioration in product quality of thin films and even a drop in production yield, which is a problem. There is another problem that a large floor space is necessary to install the apparatus. While automated transportation of the sheet films is indispensable to solve these problems, since the sheet films F are flexible, there is one of major obstacles to automation as transportation of the sheet films F using a known transportation mechanism such as a transportation robot is difficult.